Mechanisms of clearance of duck hepatitis B virus from infected adult ducks / 中国免疫学杂志

ABSTRACT

Objective:To gain insight into the mechanism responsible for clearance of natural hepa DNA virus infections.Methods:A group of seven 2～3 month old ducks were infected intravenously with 10～20 ml DHBV positive serum containing 5?10 7 genomes/ml.Following inoculation,ducks were bled at weekly intervals to obtain serum samples for analysis of DHBV DNA and DHBsAg and anti DHBV antibodies.Peripheral blood mononuclear cells were collected at 10,35 days postinoculation(p.i) and used to conduct antigen specific blastogenesis assay.Liver samples were obtained at 5,30,60 days p.i for analysis of DHBV DNA and surface antigens and liver histology.Results:Infection of all 7 animals with approximately 5?10 8～1?10 9 DHBV genomes led to a transient viremia after an incubation period of 1 to 2 weeks.Liver samples contained multiple copies of all of the expected species of DHBV DNA replicative intermediates,including DHBV cccDNA during the peak of viremic phase.Further analysis showed that the absence of a prolonged viremia could be explained by immediate antigen specific blastogenesis and high titer of antibody response.Meanwhile,there was no obvious evidence of liver cell injury during transient DHBV infection.Conclusion:These results demonstrate that noncytopathic antiviral mechanisms make a role in hepa DNA virus clearance.